SEEING it’s set in the Catskills in the sum mer of 1960, you might suspect “The American Plan” of being another “Dirty Dancing.”

But the real dance in Richard Greenberg’s intermittently intriguing 1990 play is the tango between a domineering mother and her delicate daughter.

Think “The Glass Menagerie” and “The Light in the Piazza,” in the looming shadow of (spoiler alert!) “Brokeback Mountain.”

It’s clear from the start that Lili Adler (a luminous Lily Rabe) is a girl interrupted. There’s something pained and vacant in her blond, “Alice in Wonderland” looks, and when a sinewy young man hauls himself out of the lake onto her private dock, she’s only too eager to fall in love.

His name is Nick Lockridge (Kieran Campion), and he’s vacationing at the hotel across the way with the Kahkstein family (pronounce it at your peril), whose daughter he’s dating between meals. (And on the hotel’s American Plan, there are lots of ’em.)

Lili has her own baggage. She’s dropped out of Sarah Lawrence and is tethered to her mother, the elegant German-Jewish émigré, Eva (Mercedes Ruehl), who may or may not have murdered Lili’s father.

Does Nick really write for Time? What happened to his father? And just how well does he know Gil Harbison (Austin Lysy), that other WASPy refugee from across the lake?

Ruehl, one of our great stage actresses, makes Eva a force of nature. But even as she gleefully extols the excesses across the lake (“a steak the size and shape of a jackboot”), she’s constrained by an ungainly German accent.

It’s like seeing a beautiful woman who’s been zipped into a fat suit and can’t get out. You wish someone had sprung for a dialog coach.

And, while we’re at it, a set. Jonathan Fensom’s scenic design seems downright skimpy, revolving as it does around a dock, with a backdrop of pleated curtains. There’s a table and chair set, too, which apparently serve both the lake house and the Adlers’ Manhattan apartment.

Britain’s David Grindley, who helmed the brothers-in-arms drama “Journey’s End,” seems on firmest ground in the scenes between Nick and Gil. That’s when the writing is sharpest, too.

Greenberg’s at his best when his characters float on a stream of their own musings – it’s how “Take Me Out” took off, how “The Dazzle” dazzled. Here, in this earlier effort, they’re more stunted: It’s hard to believe anyone, even a writer for Time, would use the verb “purpled.”

“Happiness exists . . . but it’s for other people,” Lili concludes, sounding a little like the ogre’s parents in “Shrek: The Musical.”

But there’s too much talk, too little action. It made me long to swim across the lake and party with the Kahksteins.